Presser-foot lifting mechanism for sewing machines



PREssER-FooT LIFTING ArvIEcHANIslsa. FOR SEWING MACHINES R. BECKER May 28, 1946.

Filed Jurie 9, 1945 5 Sheets-Sheet 1 May 28, 1946. R. BECKER 2,401,216

PRE'ssEmFOo'T LIFTING MECHANISM FOR SEWING MACHINES Filed Junel 9, 1945 L s sheets-sheet 2 13E f 51.; I g 'i n 6 f""' 35 Ik? 1.

May 28, 1946. R. BECKER 2,401,216

PRESSER-FOOT LIFTING MECHAIIISlV-I FOR SEWING MACHINES Filed June 9, 1945 3 Sheets-Shee't' Patented May 28, 1946 -UNI`TED STATES PATENT OFFICE :PRESSER-FOOT ILIFTING MECHANISM FOR SEWING MACHINES Rudolph Becker, North Plainfield; N..I.,"assignorA to "The, Singer Manufacturing Com-pany,- Elizabeth, N. J., a corporation of'NewJersey Application June 9, 1945, Serial No..598,437

9 Claims. (C1. i12-23s) 'This invention relates to "sewing machines-'of themultiple needle, heavy duty typeand` more particularly itc improved Ymanually `actuated means for lifting the presser-foot I(or presserfeet) of suchvmachines.

lin heavy vduty sewingimachines it isfcommon practice toA havefone `or more presser-bars` vertically movable inabracket-arm 'heady to have a presser-foot attached to the lower rend of. each presser-:bam and to :shave a 4relatively H'heavy pressurespring acting `on each presserbartoldepressithe Ipresser-foot` onto the:v Work therebe neafth, The;presserfoot (or'feet) holds Vthe work on: the :cloth plate :during the' time the needle fis within the work and cooperates-withbaffeeding mechanism, While the needle 'is out 'of' the work, to'effect feeding ofthe Work'through'the machine.

It tis also vcommon fpractice to 4utilize the presser-bar :lifter to release the needle-thread tensions: simultaneously-with the 'lifting of .the

` presser-feet. This is effected by 'compressingthe tension springs-'away from the tension'. disks thus relieving the' pressure y'of the disks on the Cthread. When the machinecontain's a considerable number of needles, and'va `corresponding `number of threadV tensions, thisrele'asing of the tensionsV adds considerablyfto .the loadirnposed upon the presser-bar lifter.

In' the operation of a sewing machine; -it is frequently necessary 'that the `operator lift the presser-foot (orfeet) by hand. Inheavy `duty machines, and especially those employinga plurality f `spring-depressed presser-bars and a considerable number of thread tensions; the totaldownwardpressure which hasl Ito be overcome by the-presser1lifter1is relatively great and'therefore the repeated llifting ofthe presser-feet, 'in opposition'to such afspring pressurajis 'arduous and tiring to the operator.

.This invention therefore has a, primaryobject to provide an improved manually operable presser-foot lifting mechanism by 'means cf` which the heavy spring. pressure of the `presserdevice ofa .heavy duty sewingmachine .may be easily overcome, thus making itv possible for the operator --to raise andnlower the ,presser-device repeatedly Without annoyance. or fatigue.

Y Withthe above. andother objectsA invievv, as

will hereinafter appearpthe inventioncomprises the devices, combinationsuand arrangements of parts hereinaftersetforth andrillustrated .in the accompanying drawings of a* preferred `-embodiment of the invention, fromwhichi-the several features' of` :the invention and the advantages attained. therebywill be readily-understood by those skilledin the'art.

In thedrawings,

Fig. 1 is va rear elevationof a-sewing machine embodying the present invention.

Fig..2is an enlarged right end'vieW, partly in section, of the bracket-'arm head,shown in Fig. 1, showing the -improved presser-foot lifting mechanism -associated therewith.

"Fig.13 isa fragmentary vertical section substantially on ,the line "3--3rof Fig. 2.

`"Fig. 4'isa horizontal sectional view substantially 'ron -the line 4-4 -of Fig.' 2.

Referring-more specifically to the-drawings,-the invention -is disclosed vasembodiedl in a sewing machine 4having :a work-support -I ,afbraoketarm comprising a standard 2 Yfand an" overhanging arm 3 terminating in a head 4, and a lower four-motioned nwork-feeding mechanism, designated generally as fs-which operates :through -suita'ble 'slots in the work-support. Mounted `in `Cbearings f5. -in thenheadfll,V for vertical .,recipro'cation, -are twopresserbars to the `flowerfend. of -each of which is secured afbracket 11i-carrying `a "pressen-foot i 'I. The ipresser-barsf-G are laterally spaced from each other crosswise tof f the lines 'of 'seam' formation. Each presser-bar -is depressed by a relatively strong spring= 8, the upper end of -which abuts the-'lower-end ofaspring tensionfadjusting screw I `I` threadedcinto a bushing-ecarried by ythe head 4. -The lower end'ofeach spring fis'locatedwithinaboreI formed infoneofthe vpresser-barsand bea-rs V:against the lower wall f thereof. `Each spring-tension-adjustingscrew I I hasfon its -lowerfend; a spring-guiding rod I2. By adjusting 'the screws II, 'any desired-spring pressure mayibe applied "to the presser-'bars fandto the kpresserfeetH-carried thereby.

Secured upon-each of thepresser-bars6,within the-head1, 'is Va :lifting fcollarz-I 3 carrying a" rollerstud I 4. i Thesestuds foverlie,=and are`-engaged by, the flattened forwardends- I'Eof two presser-'bar' liftingfarm-sl 5, the vhubs PI-iib 'of Lwhich are secured taken .upon' a presserebar lifting shaft `lli;jciur-'naled'at the. frear side' offthe"rbracketharmfaandlengthwise thereof' inffbearings fIiI. i Fixedytothevoppositeend=of"theshaft-l 6,;rearwardly of the standard 2,'is anarm'lI-B4 -to-whichis `connected the up per end of a treadle-actuated chain I9, or similar connection. "Thus by theoperationl o'f a suitable treadle 'tnot shown) -thes'haft 16 and the-presserbar lifting *arms1 I5` mayibe turned counterclockwise; asviewed'iri vig;`2 thereby lifting the presserbars-6 and the presserefeet 1 A'carried thereby. ffnr'torsom spring -ISa 4surrounds the shaft "I6 adjacent the rear bearing I1 and has one offset end Ib fitted into an aperture in a collar IGc secured to the shaft I6, and its other offset end Id bearing against the standard '2. This spring normally biases the shaft I6 in a clockwise direction, as seen in Fig. 2, and thus maintains a slight clearance between the portionsr Ia of the .levers I5 and the studs I4. This permits the presserbars to have their normal up and down movements, under the infiuence of the feed-dog, without affecting the presser-foot lifters.

Carried by a bracket 20, secured to the head 4,

is a plate 2l which, in turn, carries a pluralityV of thread tensions 22; one for each needle-thread but of which only three are shown. Each thread tension includes a supporting stud 23, a pair of disks 24, between which the thread passes, a tension regulating nut 25 threaded Aon the stud 23 and a coil spring 26 surrounding the stud between the nut 25 and a washer 21 bearing upon the top of the upper tension disk. Tension on the thread may be released by upward compression of the spring 26 by upward endwise movement of a tension-releasing pin 28 which extends through the tension disks and has its upper end engaging a portion of the washer 21. The lower ends of the pins 28 project below the plate 2| and rest upon a vertically movable frame 29 carrying, at its under side, an angle plate 29a which is supported upon the'upper'end of an arm 30 secured upon the hubs I5b of the presser lifting arms. Thus each oscillation of the shaft I6 to lift the presser-bars also effects release of the needlethread tensions. Tension releases of this general natureV are well known; being shown, for example in United States lpatents of A. H. DeVoe, No.'1,146,405, July 13, 1915, and No. 1,293,725, Feb. 1l, 1919.

This invention provides an improved powermultiplying hand-actuated meansV for turning the shaft I6 to effect lifting of the presser-bars and releasing the needle-thread tensions. This means comprises a relatively long manually operable lever 3| fulcrumed on a stud 32 threaded, at 33, into the bracket-arm'head 4. Cooperating with Ythe lever 3l is a relatively long arm 34 secured to the forwardend of the shaft I6, as by setscrews 35. Formed on the under side of the arm 34 is a cam surface 36 adapted, during a counterclockwise movement vof the handlever 3I;(Fig. 2) 'to be engaged by a roller stud 31`carried-by the hand-lever., As the hand-lever is turned' .counterclockwise' from the position shown in full lines in Fig. 2 to that indicated in dotted lines, the coaction between'the vstud 31 andthe surface 23S-cams the armr 34 upwardly, thus turning the shaft I6 counterclockwise and, through arms I5, studs I4 and collars I3, lifting the presser-,bars and the presser-feet carried thereby. 'A stud 38,"carried by the arm ,34, lies iny thepath of the lever 3l vand limits its movement in one direction, thus predetermining' the elevated position of the'pres'ser-feet. In'the'position indicated'i'n .dotted lines in Fig. 2'the` lever 3| is'overbalanced toward the rear of the machine and when once moved tothat position will remain there, Vholding the presser-feet elevated, until the lever is gain' moved forwardly by hand. t v

The hand-leverSI is so vconstructed and arranged thatgwh'en it isturned to lower the presser-feet, the lever is overbalanced toward the front of the -machineand therefore gravitates to the position shown in full lines inFig. 2 in which the lever rests against va stop screw 38 Carried by the outer end of the arm 34. Thus the roller 31 is prevented from accidentally getting beneath the arm 34 and maintaining it elevated when the presser-bar is -lifted by the treadle connection I9.

From the foregoing it will be apparent that the relatively long lever 3| and the power multiplying connection between that lever and the shaft I6, including the arm 34 andthe cam and roller connection between the lever 3| and the arm 34, afford an easily actuated means whereby the presser-bars may be lifted and the needlethread tensions released by the application of a relatively light pressure upon the lever by the hand of the operator.

vHaving thus set forth the nature of the invention what I claim herein is:

1. In a sewing machine having a head and a Y spring-depressed presser-bar slidingly mounted therein; a presser-bar lifting means comprising a rock-arm journaled rearwardly of said presserbar and operatively connected therewith, a manually operable presser-bar lifting lever fulcrumed on said head, and a power multiplying connection between said lever and said rock-arm.

2. In a sewing machine having a head and a spring-'depressed presser-bar slidingly mounted therein; a presser-bar lifting means comprising a first rock-arm journaled rearwardly of said presser-bar and operatively connected therewith, a second rock-arm operatively connected with said first rock-arm, a manually operable lever fulcrumed on said, head, and means actuated by said manually operable lever for turning said second rock-arm and thereby said first rock-arm to lift said presser-bar.

3. In a sewing machine having'a head and a spring-depressed presser-bar slidingly mounted thereina presser-bar lifting means comprising a first rock-arm journaled `rearwardly of said presser-bar and operatively connected therewith, a second rock-arm operatively connected with said first rock-arm, a hand-lever fulcrumed on said head, and a stud carried by said hand-lever and engaging said second rock-arm during one movement of the hand-Iever`toV turn said rockarms and effect lifting of said presser-bar.

4. In a sewing machine having a head and a spring-depressed presser-bar slidingly mounted therein; a presser-bar lifting means comprising a first rock-arm journaled rearwardly of said presser-bar and operatively connected therewith, a second rock-arm journaled coaxially with said first rock-arm and operatively connected therewith, a cam surface on said second rock-arm, a manuallyv operable presser-bar lifting lever ful crumed on said head, anda stud carried by said lever and engaging said cam'surface during one movement 'of said lever to turn-said second rockarm and thereby the first rock-arm to lift said presser-bar. Y

5,'In a sewing machine having a head and a spring-depressed presser-bar slidingly mounted therein; a presser-bar lifting means comprising a first rock-arm'journaled rearwardly of said presser-bar .and operatively connected therewith, a second rock-arm operatively connected with said first rock-arm, an oscillatable hand-lever fulcrumed on said head, a cam andr stud connection between said hand-lever and said second rockarm whereby movement ofthe hand-lever in one direction turns said rock-arms and effects lifting of said presser-bar,'andstopsfor limiting the movement of said hand-leverfin it' s"opposite directions of movement. 'Y v 1 6. In a sewing machine havinga bracket-arm terminating in a bracket-arm head, a shaft journaled lengthwise of said bracket-arm and aV spring-depressed presser-bar slidingly mounted in said bracket-arm head; presser-,bar lifting means comprising a first rock-arm having one end secured to said shaft and its other end operatively connected with said presser-bar, a second rockarm secured to said shaft, a manually operable lever, and an operative connection between said lever and said second rock-arm whereby move- 'ment of said lever in one direction turns said second rock-arm, shaft and rst rock-arm to lift said presser-bar.

7. In a sewing machine having a bracket-arm terminating in a bracket-arm head, a shaft journaled lengthwise of said bracket-arm and a spring-depressed presser-bar slidingly mounted in said bracket-arm head; presser-bar lifting means comprising a first rock-arm having one end secured to said shaft and its other end operatively connected with said presser-bar, a second rockarm secured to said shaft, a manually operable lever, an operative connection between said lever and said second rock-arm whereby movement of said lever in one direction turns said second rockarm, shaft and first rock-arm to lift said presserbar, and supplemental treadle-actuated means for turning said shaft to lift said presser-bar, said manually operable lever being normally biased to an inoperative position in which its connection with said second rock-arm is rendered ineffective during the lifting of said presser-bar by said treadle-actuated means.

8. In a sewing machine having a head supporting a plurality of spring-closed thread tensions and having slidingly mounted therein a plurality of spring-depressed presser-bars; means for simultaneously lifting said presser-bars and releasing said thread tensions, comprisng a rockshaft, means actuated by the movement of said rock-shaft for releasing said thread tensions, a pair of arms each having one end connected to said rock-shaft and its opposite end operatively connected with one of said presser-bars, a manually operable lever fulcrumed on said head, and a power multiplying connection between said lever and said rock-shaft for oscillating said shaft to lift said presser-bars and release said thread tensions by a relatively light pressure applied to said lever.

9. In a sewing machine having a head supporting a spring-closed threadtension and having slidingly mounted therein a spring-depressed presser-bar; means for simultaneously lifting said presser-bar and releasing said thread tension, comprising a rock-shaft, means actuated by the movement of said rock-shaft for releasing said thread tension, a rock-arm having one end connected to said rock-shaft and its opposite end operatively connected with said presser-bar, a

-second rock-arm secured to said rock-shaft, a

hand-lever fulcrumed on said head and operatively connected with said second rock-arm whereby movement of said handelever in one i direction turns said second rock-arm and thereby said shaft to lift said presser-bar and release said thread tension.

RUDOLPH BECKER. 

